In general, a sleeping bag is a bag that is warmly lined or padded for sleeping outdoors, for example in a camper or a tent. Sleeping bags may also be used for sleeping on the floor inside a house, such as on a sleepover, or may be used as convenient bedding material when traveling.
Sleeping bags typically include a bottom portion, upon which an individual within the sleeping bag lays, and a top portion which extends over the person to cover the individual. Often, the top and bottom portions are made of a single, large rectangular insulated or padded fabric that is folded and attached along bottom and side edges to form the bag. The attachment is typically made by a zipper.
Sleeping bags are often folded in half lengthwise and rolled into a tight ball for transportation and storage. After rolled, most rolled rectangular sleeping bags are tied with tie cords, compression straps, or elastic straps, or may be otherwise secured so that the sleeping bag does not become unrolled during transportation and storage.
One problem associated with rolling of sleeping bags is that once the sleeping bag is folded (for example, lengthwise), it is often difficult to roll the sleeping bag without the edges of the sleeping bag being forced apart during the rolling process. For this reason, many users find it difficult to roll the sleeping bags into a tight, tidy configuration so that closure may be secured for transportation and storage. Moreover, even if a user can roll the sleeping bag into the tight configuration, the user may find tying the bag difficult, because tying the cords requires two hands, leaving no hands for holding the bag in the tightly rolled configuration. Often a user has to sit on the bag while tying it, or drive his or her knees into the bag to keep it from unrolling.